An airline expert just revealed the secret to booking cheap flight tickets, but it's not doing so in advance

Booking a seat on a flight that's experiencing low demand could save you money on airfare.Kritchanut/Shutterstock
Travel-booking websites like Expedia routinely release studies revealing the best days to book a cheap flight, but it turns out that when you fly is far more important than when you book, according to Tim Lyon, managing director of revenue management at American Airlines, who was quoted in a report from Quartz.

By opting to fly at an earlier or later time of the day, midweek, or outside busy holidays, travellers have a better chance of securing more affordable tickets.

While it might sound like obvious advice, Lyon said that airlines are motivated to set their ticket prices according to the demand on a particular flight and route, as well as the number of seats that are being sold. Airlines therefore tend to decrease their prices on flights that experience low demand.

"In the end, the seats are going to fly, and what revenue management does is put the most revenue on the plane, regardless of cost," Lyon said.

Carriers can amend the cost of airfare a number of times a day, so it makes sense that airlines cut ticket prices when they want to fill empty seats.

The length of a flight is also worth considering when looking to find a cheap ticket, Lyon said — especially if it's a drivable distance.

"There are things we have to take into account to say, 'I know I am competing with a car here,'" he said. "Once you get away from [short routes], it migrates into absolute demand."